How can I change the transform by minimal code?
if you want to get exact code you shouldn't change transform in view port.
when you change the transform in this panel it works:


Location
import bpy

obj = bpy.context.object
obj.location = (0,0,0)

Rotation
import bpy
import math

obj = bpy.context.object
obj.rotation_euler = (0,math.radians(90),0)

Scale
import bpy

obj= bpy.context.object
obj.scale = (1,1,1)